This invention relates to an apparatus for controlling the opening and closing of a retractable head lamp, and more particularly, to such an apparatus in which a normal position of the head lamp is positively held even if an instantaneous opening signal or closing signal is applied.
Retractable head lamps for automobiles generally have a problem in that the head lamp is sometimes stopped in its slightly open condition or in such a position that the lamp tends to be closed from its fully open condition. Head lamps of the retractable type form a part of an outer surface of a vehicle body, and therefore, the external appearance thereof is impaired when the lamp is in a half-open or partially open condition. If forcible pressing of a half-open or partially open lamp is applied from the outside, the opening and closing mechanism thereof may possibly be damaged.
FIG. 1 shows an example of a conventional apparatus for controlling the opening and closing of a retractable head lamp. This conventional apparatus comprises a motor 1 for opening and closing a head lamp via an opening and closing mechanism 20 (schematically shown), a position detecting member 2 which is rotated by the power of the motor 1, a relay circuit 3 for cutting off energization of the motor 1 when the position detecting member 2 detects the open position or closed position of the head lamp, and a manually operable hand switch 4. The hand switch 4 comprises a movable element 4a, a terminal 4c for transmitting a forced head lamp opening signal in response to the movable element 4a contacting terminal 4c, a normal terminal 4d, a movable element 4b, a terminal 4e for transmitting a lighting and opening signal of the head lamp 21 in response to the movable element 4b contacting terminal 4e, a small lamp (i.e. parking lamp) lighting terminal 4f, and a terminal 4g for transmitting closing signal of the head lamp responsive to the movable element 4b contacting terminal 4g (the headlamp 21 is turned off when movable element 4b is moved to terminal 4g).
The position detecting member 2 comprises a circular sliding surface 2a having one surface formed of a conductor (hatched portion in FIG. 1), an opening signal stopping portion 2b in which an outer circumferential portion of the conducting sliding surface 2a is cut away to form an insulating portion, and a closing signal stopping portion 2c (insulating portion) formed by similar means in an outer circumferential direction from the center. A contact 2b' connected to the terminal 4e of hand switch 4 is in contact with an outer circumferential portion of the sliding surface 2a including the opening signal stopping portion 2b, and a contact 2c' connected to the terminal 4g is in contact with a portion of sliding surface 2a including the opening signal stopping portion 2c. A further contact 2d is connected to a relay coil 3a of the relay 3 and assumes a position in contact with the conducting portion of sliding surface 2a irrespective of the position of the detecting member 2.
The head lamp opening and closing mechanism 20 may be a conventional linkage-type mechanism such as that shown in U.S. Pat. No. 4,282,561, issued Aug. 4, 1981, the contents of which are incorporated herein by reference.
Accordingly, if the movable element 4b of the hand switch 4 is switched from the illustrated position (when the retractable head lamp is in the open position and when the head lamp 21 is lit) to the terminal 4g, the head lamp 21 is turned off and the relay coil 3a is energized (via contact 2d) to connect the movable contact 3b of relay 3 to the power source V, as a consequence of which the motor 1 is driven to move the head lamp to the closed position via mechanism 20. This operation remains in effect until the closing signal stopping portion 2c reaches the position of the contact 2c' by rotation of the position detecting member 2 which is coupled to the motor 1. At this point, contact 2c' is no longer electrically connected to contact 2d and the relay 3 is de-energized to stop the motor 1. This stopped position is the position where the head lamp is in the fully closed condition.
When the movable element 4b is switched from the terminal 4g to the terminal 4e, the head lamp 21 lights and the relay coil 3a is energized through the contacts 2b' and 2d, as a consequence of which the motor 1 is driven via power source V and then stops when the opening signal stopping portion 2b of the position detecting member 2 reaches the contact 2b' in a manner similar to that as described above. This stopped position is the position where the head lamp is in the fully open condition. It is noted that when the movable element 4b is switched from the terminal 4e to the terminal 4f, the head lamp 21 is extinguished and the small lamp 22 (i.e. parking lamp) is lit, the other operating conditions remaining unchanged.
The movable element 4a is provided to bring the head lamp into the open condition irrespective of the position of the movable element 4b, and this action can be achieved by switching the movable element 4a to the terminal 4c.
As described above, the conventional control apparatus of FIG. 1 can fulfill the function generally required of the retractable head lamp. However, in the case when the hand switch 4 is instantaneously operated, for example, suppose that the head lamp is open (FIG. 1 position) and that the movable element 4b is quickly or instantaneously switched to the terminals 4e.fwdarw.4g.fwdarw.4e, the motor 1 is driven instantaneously and therefore, the head lamp tends to be driven to the closed condition and the position detecting member 2 is also rotated by a small amount. Since this is a matter of instantaneous operating, the contact 2b' therefore stays within the region of the opening signal stopping portion 2b. But, the head lamp becomes stopped at an uncertain position where the head lamp is slightly closed from the normal fully open position. This means that the head lamp is not properly aimed. A similar inconvenience occurs when the head lamp is fully closed and the movable element 4b is instantaneously switched from the terminal 4g to the terminal 4e and then back to terminal 4g. In such a case, the relay coil 3a is instantaneously energized through the contacts 2b' and 2d with the result that the motor 1 is instantaneously driven and the head lamp is slightly moved toward its open position, whereas the contact 2c' stays within the region of the closing signal stopping portion 2c. Thus, the head lamp is off, but becomes stopped in a position where the head lamp is slightly moved toward its open position, whereas the contact 2c' stays within the region of the closing signal stopping portion 2. Thus, the head lamp is off, but becomes stopped in a position where the head lamp is slightly open. This impairs the appearance of the vehicle and if the head lamp is manually pressed toward the fully closed position, damage to the operating mechanism may occur.